Col della Boaria

Overview

Col della Boaria is a hors-catégorie (HC) climb on the French side of the border, running 7.5 km from base to summit. Over that distance it delivers a net elevation gain of 1,162 m, lifting you from a start elevation of 979 m to a summit at 2,141 m. The average gradient across the full climb is 15.4%, which puts it well beyond the range of ordinary hard climbs and squarely into the territory reserved for the steepest paved ascents in the region.

The number that shapes the day, though, is the gap between net gain and total ascent. You climb 1,162 m net, but the total ascent is 1,281 m — a difference of 119 m. That means the road gives back roughly 119 m of descent somewhere on the way up. Those downhill stretches interrupt your rhythm, force you to re-accelerate, and add climbing that never shows up in the net figure. On a climb this steep, every recovery you take is followed by a fresh surge back onto the wall.

How the Gradient Unfolds

A 15.4% average is not a climb you settle into. Averages this high hide the fact that some pitches are far shallower and others are brutally steep — the mean is dragged up by ramps that punch well into the twenties. Because the climb includes 119 m of descent inside its 7.5 km, the profile is not a smooth line; it steps up, eases, and steps up again.

• Short recovery or descending sections where the road briefly loses altitude — use them, but expect them to end abruptly.
• Repeated short, steep climbs stacked between those dips rather than one continuous grade.
• A steepest ramp far above the 15.4% average, where you will be out of the saddle and grinding at your minimum cadence.

Pacing Notes

On a steady climb you can chase an even effort. Here the undulation makes even-speed pacing a trap: holding one speed means over-cooking the steep ramps and coasting the dips. Anchor instead to a target sustainable power output and let your speed fluctuate — spin faster where it flattens, accept a crawl where it kicks up. Know your ceiling before you start; the FTP estimator gives you a working number to pace against. Bank nothing on the descents. On a 15.4% average, going into the red early on any ramp ends the climb for you.

Gearing

Gearing is decided by the steepest pitches, not the average. Bring a compact or sub-compact chainset and pair it with a wide-range cassette — a 34×32 or 34×34 is a sensible floor for a climb of this gradient. The goal is to keep a turnable cadence on the steepest ramp rather than mashing a gear you cannot rotate. Check your setup before the ride; discovering you are under-geared on a 15.4% wall is a mechanical you cannot fix on the road.

Summary

• Length: 7.5 km
• Average gradient: 15.4%
• Net elevation gain: 1,162 m
• Total ascent: 1,281 m
• Category: HC

Col della Boaria is a short climb by distance but an exceptional one by gradient. Respect the undulation, pace to power, gear low, and it becomes a hard day rather than a broken one.